Analysis of the dynamic behavior of a frame building considering the multilayered nature of the soil foundation

The influence of rolling stock loading on a twenty-three-story frame building located near the movement of railway trains in an urban area was investigated. Mathematical modeling of the dynamic behavior of multi-story buildings subjected to rolling stock loading was performed using a two-stage numerical method. In the first stage, a finite element model of the multilayer soil foundation along with the ballast prism was created in the NASTRAN software complex, represented as a planar elastoplastic half-space with a length of 200 m and a depth of 30 m. A real geological cross-section consisting of five layers with different physical characteristics was used. The rolling stock load is represented as a vertical periodic excitation, concentrated at the center of mass of the system consisting of the bogie frame, the wheelsets of a freight wagon, and the ballast prism. Modal analysis of the soil foundation and the ballast prism was performed using the Lanczos method. The influence of rolling stock loading on the dynamic behavior of the soil foundation was investigated using the fourth-order Runge-Kutta method. Horizontal and vertical displacements and accelerations of the soil were obtained at various distances and depths of the foundation model from the railway track axis. In the second stage, a 3D model of the monolithic frame building was created in the SCAD software complex. Modal analysis of the structure was performed using the subspace iteration method. Two calculation options for the multi-story building were considered. The first calculation was performed for the action of design load combinations: permanent, sustained, and short-term (snow, wind load). In the second calculation option, the stress-strain state of the building was investigated using the spectral method under the action of design loads and kinematic soil excitation, applied along the height of the building's foundation in the form of acceleration vectors. The accelerations were considered in two directions and added to the design combinations along the two directions of wind load influence. A comparison of the two calculation options was performed to check the reliability and structural safety of the building.